Current-Controlled Oscillator Voltage Droop Detector
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Solution Overview
Problem
Existing digital droop detectors are highly sensitive to voltage and temperature dependencies, requiring complex 3D matrix calibration, which limits their utility in real-time applications.
Innovation Solution
A current-controlled oscillator (CCO) with analog bias is used to measure voltage droops, decoupling DC voltage and temperature dependencies, allowing for accurate measurement of AC droops and temperature independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If digital delay circuits (CPM/TRC) are used to measure voltage droops, then the detector can be simpler to design and synthesizable, but the delay is highly sensitive to Vcc DC level and temperature, requiring complex 3D matrix calibration
Solution Approach 1:
The patent introduces an analog intermediary stage (transistor pair M1a-M1b with resistor R1) between the digital supply node and the delay circuit. This analog stage acts as a mediator that converts voltage droops into current variations, which then drive the delay circuit. This intermediary conversion decouples the digital delay measurement from direct sensitivity to Vcc DC level and temperature, reducing calibration complexity while maintaining design simplicity.
Solution Approach 2:
The patent replaces the purely digital delay measurement approach with an analog-current based mechanism. Instead of directly measuring digital delay (which is sensitive to voltage and temperature), the system uses an analog current-controlled oscillator whose frequency is driven by current variations from the voltage droop. This substitution of digital measurement with analog current-driven mechanism eliminates the need for complex 3D matrix calibration while maintaining measurement accuracy.
2Ease of operation
If analog comparators are used to detect voltage droops, then the detection can be straightforward, but the detection speed is limited by the power consumption of the comparator
Solution Approach 1:
The patent employs a dynamic current-controlled oscillator whose frequency continuously adapts to the instantaneous current conditions in the power delivery network. The oscillator frequency is proportional to the current variation caused by voltage droops, enabling fast detection without requiring high-power comparators. The dynamic adjustment of oscillation frequency based on real-time current conditions allows rapid droop detection while maintaining lower power consumption.
Solution Approach 2:
The patent changes the detection parameter from voltage threshold comparison (analog comparator approach) to frequency measurement of a current-controlled oscillator. By converting voltage droops into current variations and then into frequency changes, the system achieves faster detection speed. The frequency measurement approach is inherently faster than voltage threshold comparison because it directly tracks the dynamic current changes without the speed limitations imposed by comparator power consumption.
3Reliability
If guardband is added to Vcc to mitigate timing errors during droop, then timing errors can be reduced, but power consumption increases significantly due to Vdd2 dependency
Solution Approach 1:
The patent implements a feedback mechanism where the current-controlled oscillator continuously monitors the actual current conditions in the power delivery network and adjusts its frequency accordingly. This feedback loop enables real-time detection of voltage droops and their impact on timing, allowing the system to adapt dynamically without requiring excessive guardband. The feedback-driven frequency adjustment provides timing information that can be used to optimize performance while minimizing power consumption.
Solution Approach 2:
Instead of applying excessive guardband to completely eliminate timing errors, the patent uses a partial action approach by measuring the actual droop magnitude through the current-controlled oscillator and adjusting timing parameters accordingly. The system measures only the necessary information (current variations) and applies minimal corrective action, avoiding the excessive power consumption associated with large guardband while still achieving adequate timing error reduction.
Data Source
AI summary
A method for measuring voltage droop and temperature in a circuit include using capacitive coupling to couple a bias voltage of a current controlled oscillator (CCO) to a noisy digital Vcc (VCCD) supply, so that a frequency of the CCO is independent of a DC Vcc level of the noisy VCCD supply and the CCO measures an AC voltage droop of the noisy VCCD supply and a temperature which is dependent upon the AC voltage droop.